At Kern Junction, the double track BNSF (ex-Santa Fe) and double track UP (ex-SP) lines come together on the tracks built by the SP for the passage over Tehachapi Pass to Mojave. Kern Junction, at an elevation of 417 ft., 17 ft. higher than the former SP Bakersfield station only 0.7 miles further west, is controlled by BNSF, at BNSF MP 885.2, and is at MP 313.6 on the UP. At Kern Junction, in an industrial area on the east side of Bakersfield, the 18-track UP Yard (fourteen of them used by the SJVR) is on the north side of the tracks. Immediately east (“south”) of Kern Junction are the leads to the wye with the Buttonwillow Branch, and then a spur, both operated by the San Joaquin Valley Railroad (SJVR). The line east from Kern Junction heads roughly east-southeast over almost level ground, between industrial buildings, some of which have, or used to have, rail access. The line is Double-Track, with Absolute Block Signaling, as far as Sandcut, more than ten miles to the east (“south”). When the new signals for Positive Train Control compatibility were installed in 2015, enough hardware was installed for bi-directional signaling when the switch to Two Main Tracks, CTC, occurs, but as of Auguest 2016, the signal heads for the 'against-the-current' direction on each track are still turned away from the track.
This line is part of the UP Mojave Subdivision (mileposts from San Francisco).
East of the “south” end of Bakersfield Yard, Mount Vernon Avenue crosses over the tracks on a bridge, while Edison Road parallels the tracks on the south side at Quantico (MP 314.8), east end of the yard. There is a signal bridge and another signal at MP 315.1, after which Oswell Street crosses over on a bridge. There is a signal at MP 316.1, and Fairfax Road crosses over the tracks on a bridge. At Magunden (MP 316.6, el. 425 ft.), where there is a siding on the south side, the branch to Arvin, served by the SJVR, heads off to the south of the tracks across Edison Road. There is another signal at MP 317.5, Route 184 crosses the tracks at grade, another signal at 317.?, grade crossings at an industry, and at Vineland Avenue (MP 318.5), a detector at MP 318.8, signals at MP 318.9 and 319.2 and lineside industries including Hancor, the Giumarra Winery and JR Simplot on the north side of the tracks, on either side of a grade crossing at Giumarra Park Road (MP 319.5).
There is a grade crossing at Pepper Drive, followed by many packing house facilities including KingPak Farms, J&J Cold Storage, TreeRipe Oranges, Sunny Farms, Baker Produce, all in very old buildings, and Progressive Farms, MR Swanson, and Kirschenman Enterprises, on the south side, the Edison Passing Track, Eugene Frost Trucking & Sales, Lehr Brothers, Big L Packers and Kennebeck Storage on the north side, Kundert Farms on the south side with the signal at MP 320.3 (Edison, el. 525 ft.) adjacent on the tracks, a road crossing at Johnston Farms (on the north side), a signal at MP 320.8 and the Comanche Road grade crossing. There are signals at MP 322.1 and 322.4, now out in the countryside, a grade crossing at Tejon Road, a signal at MP 323.7, a grade crossing at Tower Line Road, a signal at MP 323.8, and a grade crossing at Neumakel Road ( MP 324.82).
There are crossovers and signals (including a cantilever bridge at the east end) at Sandcut (MP 325.0, el. 871 ft.), where control changes from DT ABS to Two Main Tracks, CTC. With the new signal installation in 2015, all the signal bridges have been swept away between Kern Junction and Sandcut, with the new signaling being ready for Two Main Tracks, CTC, but not yet installed as such, as mentioned above.
At this point, there is a sand dune that represents the first step into the mountains; the tracks cut through the ridge formed by this dune in the ‘sandcut’, and then curve to the northeast to drop down the eastern side of the dune, turning almost due east at the bottom of the slope. Here, there is a helper setout track on the south side of the line, and a crossover permitting access to the track on the north side of the line, at MP 326.9 , followed by a bridge over Walker Basin Creek. The road is still paralleling the tracks on the south side, all the way along here. There is a (former?) fertilizer plant on the south side of the tracks, with two more helper tracks on the north side, followed by the signals and south end of two main tracks (dropping down to single track, CTC) at Bena (MP 328.0, el. 876 ft.), where there was once an SP concrete phone booth.
There is a bridge over Bena Creek, as on the road running alongside to the south, a high-wide detector at MP 328.6, intermediate signals at MP 329.5, and a bridge (single span 'plus', wooden, prior to 2007, five span concrete since) over Caliente Creek at MP 330, at which point the road turns away from the line and heads into the adjacent hills to the south. At Ilmon (MP 330.6, el. 1,025 ft.), there are signals where another stretch of 2MT CTC starts. The line now follows the north side of Caliente Creek as it twists back and forth, past a bridge over a culvert, intermediate signals at MP 332.1/.2/.3/.4, curves both ways past the former location of Tunnel #½, daylighted after a flood in the early 1980s, and a private dirt track grade crossing, and through the Caliente Narrows, where there are intermediate signals (MP 333.6/.7/.8/.9), and on past a bridge over a culvert and a bridge over an arroyo to the south end of the 2MT section at Caliente (MP 335.4, altitude 1,292 ft.), where there was once an SP concrete phone booth. There is a spur on the south side of the 2MT about a mile west of Caliente, and one on the north side. From this point onwards the Cable, the line is single track, CTC, with frequent sidings, and climbs at a steady 2.2% grade with a speed limit of 23 mph (rather than 25, due to the use of concrete ties). The grade crossing at Caliente-Bodfish Road is immediately adjacent to the end of two main tracks, after which the heretofore eastward heading line makes a clockwise semicircle (‘horseshoe’) back to the west, crossing Caliente Creek and Tehachapi Creek in the process, crosses the road down from Bealville on a through girder bridge, and climbs westward up the south side of the Caliente Creek valley, overlooking the track heading the other was on the other side of the creek, with Caliente Bodfish Road running alongside to the north, further down the slope. There are intermediate signals at MP 336.3. Just before reaching the Caliente Narrows again, the line turns away south and enters 232 ft. long Tunnel #1 at MP 336.9.
At the south end of the tunnel, ca. MP 337, is another set of intermediate signals (MP 337.5), where there was once an SP concrete phone booth, after which the line curves almost northwest (with the road alongside), and then makes a counter-clockwise semi-circle back to the east, passing through 219 ft. Tunnel #2 (MP 337.8) and turning away from the road in the process. On the south side of Tunnel #2, the line reaches the north end of 13,270 ft. Bealville siding (MP 338.0), created some years ago by combining the former Allard siding at this point with the existing Bealville sidings further south, and snakes along the contour line on the south hillside, including yet another counter-clockwise semi-circle (at MP 339), intermediate crossovers at MP 339.5, el. 1,688 ft., and a dirt track grade crossing, to the south end of Bealville, where there was once an SP concrete phone booth, MP 340.6, altitude 1,826 ft. (4.1 miles, 534 ft. altitude gain from Caliente), where the Caliente-Bealville Road crosses at grade.
At this point, the line curves from southeast to due south and passes through 494 ft. long Tunnel #3 (MP 340.8), curves southeastward again to pass the former location of Tunnel #4 (daylighted after the 1952 earthquake), climbing steeply up the hillside, past Intermediate Signals at MP 341.3/.4, makes another counter-clockwise semi-circle to a point visible from the Bealville grade crossing and enters 1175 ft. tunnel #5 at MP 341.5. The north end of the tunnel is 1,942 ft. above sea level, on the hillside east of Bealville. The line now reaches the 7,530 ft. siding and north-side setout track at Cliff (MP 341.8, el. 1,994 ft.), makes another clockwise semi-circle on the exposed hillside, from which Caliente is visible, some 730-780 ft. below and to the northwest, and heading roughly east again (following the contour line along the north-facing hillside reaches the south end of Cliff (MP 343.3, alt. 2088 ft.), past a dirt track grade crossing, with 520 ft. Tunnel #7, MP 343.7, less than half a mile further along the hillside, followed by Intermediate Signals at ~MP 344, a bridge over a culvert, and a slide fence on the south side..
Tunnel #8, 689 ft., MP 344.2, follows hard on Tunnel #7, followed by Intermediate Signals at ~MP 344.5, a dirt track grade crossing, the 8,080 ft. siding at Rowen (MP 345.1, el. 2,388 ft., to MP 346.8, el. 2,509 ft.), with extra track on the south side, which is just north of and below Highway 58 between the Hart Flat and Keene exits. There is a bridge over Tehachapi Creek and a dirt road, and a detector at MP 347.0, as the line turns from southeast to east and then northeast, after which it makes another clockwise semi-circle at the Chavez Memorial location, with Intermediate Signals at MP 347.1 and a dirt track grade crossing within the curve, and then turns almost due south to reach the north end (MP 347.3) of 8,960 ft. Woodford siding at MP 347.9 (el. 2,712 ft.), with spurs on both sides, where there was once an SP concrete phone booth. Running along the east side of Tehachapi Creek, the line passes under the concrete bridge carrying Highway 58, and turns southeast, crossing the creek again and running between the Tehachapi-Woodford Road on the southwest side and the creek on the northeast side. At the Keene water facilities (owned and operated by the railroad), the line turns east to reach the south end of the siding (MP 349.7), where there was once an SP concrete phone booth, then northeast to cross Tehachapi Creek again, makes another clockwise semicircle and crosses the creek yet again, heading southwest.
The line then turns west, makes a counter-clockwise semicircle back to the west and enters 428 ft. Tunnel #9 at MP 351.0, in which it passes under the siding at Walong, crossing over directly above. This is the famous Tehachapi Loop. Walong siding, 4,800 ft. long, where there was once an SP concrete phone booth, begins at MP 351.1, with a signal bridge immediately outside the east (“south”) end of the tunnel, and curves around in a counter-clockwise direction, climbing steeply around a conical hill, and across the top of itself on an embankment until it has turned through 450º, past extra track on the south side, and is heading north. The “south” end of the siding is at MP 352.2, elevation 3,066 ft. The line then turns east again, passing through 307 ft. Tunnel #10 at MP 352.3 to emerge heading generally southeast, snaking along the southwest slope of the Tehachapi Creek valley, with Highway 58 far below to the north, beyond the creek, and Tehachapi-Woodford Road well above to the south. There are a number of widely spaced houses along the hillside above the line and below the road, as the line snakes back and forth along the hillside, following the contour of the land, for the three miles to the next tunnel, passing Intermediate Signals at MP 352.6, a dirt track grade crossing, and the north end of 6,189 ft. Marcel siding (MP 353.0), where there was once an SP concrete phone booth, and a setout track,
To improve capacity, Union Pacific, usimg funds supplied by BNSF, constructed a second track between the south end of Walong and the north end of Marcel, resulting in a section of Two Main Tracks, CTC, between MP 351.1 and MP 354.2, opened to traffic on September 5, 2016. The additional track snakes on a ledge around the end of the bluff through which Tunnel 10 passes, resulting in two separated tracks for a short distane.
The south end (MP 354.2, el. 3,299 ft.) of the former Marcel siding is now the south end opf the Two Main Tracks, followed by, Intermediate Signals at MP 354.6, a dirt track grade crossing, and a "talks on defect only" detector at MP 355.2, before reaching the ‘tunnel district’, starting with 513 ft. Tunnel #14 at MP 355.4, where the line turns from southeast to south-southeast, intermediate signals at MP 355.6/7 (between tunnels), slide fence on the south side, and then 330 ft. Tunnel #15 at MP 355.8, 259 ft. Tunnel #16 at MP 355.9 and 259 ft. Tunnel #17 at MP 356.0, all on the south wall of the narrow valley of Tehachapi Creek (with Highway 58 higher on the opposite wall. The SP searchlight signals along here were replaced by new PTC-compatible Safetran signals on March 11, 2013.
South of the last tunnel, the line, now at the bottom of the narrow valley, crosses the creek on a through girder bridge to reach the north end of two main tracks (2MT)) at Cable, MP 356.4, elevation 3,555 ft., where there was once an SP concrete phone booth, where there is also a short spur on the west side of the tracks (with a signal controlling its exit). A mile or so further along, past two bridges over culverts and near the intermediate signals at MP 357.6, the line turns due south, still deep in the valley, past a dirt track grade crossing, and a mile after that turns southwest for a short distance, turns south briefly past the location of the single Cable Crossover (MP 358.5), which crosses from Track 2 (the more northerly/easterly) to Track 1 heading south only, and then turns southeast again through the stretch that is visible from our house across the open field to the southwest, passing over another bridge across a tributary creek at about MP 358.7, enters a cut that reaches almost to Route 202, passes under the concrete bridge carrying that road and heads almost due east though Tehachapi itself.
There are intermediate signals at MP 359.4/5, and a detector at MP 359.5 where there is one last bridge across a west-flowing creek and a cantilever signal bridge at MP 360.6, governing the crossovers in Tehachapi (where the Two Main Tracks become Double-Track, Absolute Block for the ten miles to Cameron). With Tehachapi Boulevard running along its south side, the line passes the old SP Tehachapi Depot (once the only remaining complete version of a depot to that standard plan in its original location, but since burned down and replaced in kind) on the south side of the tracks, el. 3,970 ft., crosses Green Street at grade, passes the new UP Depot on the north side of the tracks and the old Water Tank on the south side of the tracks. The SP searchlight signals along here will soon be replaced by the Safetran signals, which as of March 12, 2013, have been erected and are turned sideways.
The line passes through the crossovers and past the “Turntable” Track (spur) on the north side of the tracks, and the dual-ended Lime Spur on the north side, crosses North Hayes Street at grade, passes the two K&J spurs on the south side,, and the two Chemtool spurs on the north side, a car identification scanner and the signals governing the south end of the crossovers, at MP 361.2, and crosses Dennison Road at MP 361.4. There are absolute signals at MP 362.0, handthrow switches at the south side Summit siding, MP 362.3 (on Track 1 only), the Summit itself (elevation 4,032 ft.) at MP 362.4, and dual concrete bridges carrying Highway 58 over the tracks.
There is a signaled setout track on the south side of the line at MP 363.2, a high-wide detector at MP 363.8 (moved to MP 254.3 in the last week of July, 2015), a signal at MP 363.9, and a road crossing at MP 364.?, followed by the extensive Lehigh Southwest (formerly Calaveras) cement plant and its sidings, along the north side of the tracks at Monolith (MP 365.0, el. 3,949 ft.). There is a grade crossing where Tehachapi Boulevard crosses from the south to the north side of the tracks, intermediate signals at MP 366.5/6. After the line turns southeast, Highway 58 crosses over again on another concrete bridge, and signals at about MP 368. After passing through a narrow defile on the south side of Highway 58, the line crosses Cameron Road at grade (MP 369.2, el. 3,773 ft.) as it turns east-northeast, and then through the Cameron Crossovers at MP 370.3, with appropriate signals at both ends of the crossovers. “South” of the crossovers, Track 1 of the Double Track is CTC-controlled, with Track 2 being Absolute Block, current of traffic, only.
As the line now runs along the curving southerly edge of the east-flowing Cache Creek valley, there are intermediate signals at MP 371.6/.7, 372.7 (the former ends of La Rose siding), 374.3/.4 (Warren, el. 3,440 ft.), and ?? (formerly the other end of Warren siding), with two spur for the City of Los Angeles Department of Water and Power on the south side. The line swings through a big curve to head almost due south towards Mojave, leaving behind Highway 58 which continues due east, with the connecting road into Mojave eventually coming alongside the line to the east. There is a signal bridge and a detector at MP 377.1, as the road reaches the tracks, at an elevation of about 3,000 ft. There are more signals at “Sage” (MP 379.0), and a grade crossing at Arroyo Avenue, Mojave.
There is a signal at MP 380, and the Lone Pine Subdivision trails in from the northeast at MP 380.1, just north of the north end of the seven-track Mojave Yard. Oak Creek Road passes over the north end of the yard on a concrete bridge. The site of the former Mojave depot is at MP 380.7, el. 2,749 ft., where there are more signals, the Oak Creek Industrial Lead heads west from a wye at the west side of the yard at MP 381.0, and the south end of the yard, also the point where the line passes under dual concrete bridges carrying Highway 14 and where the BNSF line to Barstow departs eastward while the UP line continues southward, is at MP 381.3, with a number of signals at appropriate places.